In construction and in public works operations, it is common practice to use an apparatus known as a "front end loader", consisting of a tractor on the front of which is mounted a large bucket which extends a considerable distance transversely of the front of the tractor. As the name implies, the loader is usually used to transfer dirt, stone, and loose material from the ground into a waiting truck for transfer to another location. While such apparatus has a wide range of functions in connection with material handling, nevertheless it is limited in the type of materials that it can handle. For instance, it is difficult with a front end loader to pick up a log and transfer it into a truck; this is because the log may be balanced on the bucket when it is close to the ground, but when the operator attempts to raise the bucket with the log on it, the log tends to roll off of the bucket either toward the tractor and the operator or away from it. Similarly, if the operator attempts to lift a bundle of brush, the bundle tends to fall apart in the process of raising it for loading into a truck, or in moving it in any way. The patent of Holopainen U.S. Pat. No. 3,273,729 shows a hydraulically-operated clamping arm that has been used in connection with a backhoe, the clamping arm being mounted on the boom. However, when one attempts to apply such an arm to a front end loader, it readily becomes apparent that there is no suitable location for the arm when it is not being used. Attempts in the past to apply clamping arms to front end loaders have been less than successful, particularly because the resulting apparatus has interfered with normal operation of the bucket, has been complicated and expensive, and has been subject to damage when the bucket is used in the conventional manner. These and other difficulties experienced with prior art devices have been obviated in a novel manner by the present invention.
It is, therefore, an outstanding object of the invention to provide material handling apparatus which extends the range of materials that can be handled by a front end loader.
Another object of the present invention is the provision of material handling apparatus, including a clamping arm mounted on a bucket for operation therewith.
A further object of the present invention is the provision of material handling apparatus having a clamping arm for use with a bucket, which apparatus is simply in construction, which is inexpensive to manufacture, and which is capable of a long life of useful service with a minimum of maintenance.
It is another object of the instant invention to provide material handling apparatus, including a bucket and a clamping arm, with means to store the clamping arm, so that it does not interfer with normal operation of the bucket when the clamping arm is not used.
A still further object of the invention is the provision of material handling apparatus, including hydraulic circuitry for operating a bucket and clamping arm in alternate modes.
It is a further object of the invention to provide material handling apparatus, including hydraulic circuitry for operating a clamping arm in conjunction with a bucket, which circuitry is capable of operating the clamping arm in the operative mode and in the storage mode.